1. Field of the Invention
The present invention relates to an endoscope, and particularly, to a connection structure of a cable to a circuit board built into a distal end of an insertion part of an endoscope.
2. Description of the Related Art
In electronic endoscopes, an imaging element is built into the distal end of an insertion part. The imaging element is mounted on a circuit board, and transmission of a video signal or the like is performed via a cable connected to the circuit board.
Generally, a bundle-wire cable obtained by bundling a plurality of single-wire cables and a plurality of coaxial cables is used as the cable. In recent years, coaxial cables tend to be frequently used from the viewpoint of improving transmission characteristics.
However, since both the shields and cores of the coaxial cable should be connected (for example, JP2010-68930A or the like), when the number of the coaxial cables is increased, there are problems in that the number of connecting terminals to be formed on the circuit board is also increased, and promotion of a smaller diameter is hindered.
For this reason, in the related art, for example, a configuration in which the coaxial cables and the single-wires cable are divided and connected above and below a circuit board (front and rear) has been proposed (for example, JP2010-68930A and JP2000-125161A).
However, in the configuration in which the coaxial cables and the single-wire cables are divided and connected above and below the circuit board, there are drawbacks in that the wiring should be divided, connection work should be performed after being divided to the front and rear of the circuit board, and time and effort are required for the wiring connection work. In order to separate and connect the cables, there is also a drawback that the strength of a connecting portion becomes weak.
JP2009-82504A is an example of related art.